Superfatted soap bars and process for their preparation



United States Patent 3,494,869 SUPERFATTED SOAP BARS .AND PROCESS FORTHEIR PREPARATION Joseph Armstrong, Norwood, N2J., assignor to Leverlli'others Company, New York, N.Y., a corporation of awe No Drawing.Filed July 11, 1966, Ser. No. 564,027

Int. Cl. Clld 9/34, 9/14 U.S. Cl. 252-109 6 Claims ABSTRACT OF THEDISCLOSURE The present invention relates to soap compositions and aprocess for their preparation and more particularly to superfatted soapbars and a process for their preparation.

Soap bars having a high content of coconut oil soap are highlyadvantageous in that they produce voluminous lather. However, such soapbars suffer from the fact that they are almost always sandy andirritating to the skin.

Therefore, it is an object of the present invention to prepare soap barshaving a high content of coconut oil soap, but which are neither sandynor irritating to the skin.

It is a further object of the present invention to provide high contentcoconut oil soap bars which produce copious lather and which bars arefirm and stable against discoloration and odor.

Another object of the present invention is to provide high contentcoconut oil soap bars which can be pro duced at a low cost and can bemade from a composition having excellent extrudability.

The process of the present invention for the preparation of highlathering, firm, stable, non-sandy, non-irritating, superfatted soapbars comprises preparing and mixing in suitable equipment, such as amixer or a crutcher, an aqueous blend containing a number of essentialcomponents discussed below.

An essential component of the aqueous blend is from about 25% to about55% by weight of a mixture in the relative amounts of from about 10% toabout 30% by weight of potassium coconut oil'soap and from about 90% toabout 70% by weight respectively of sodium coconut oil soap. The aqueousblend further contains from about to about 30% by weight of sodiumtallow soap. Another essential component of the aqueous blend is fromabout 2% to about 8% by weight of an acidulating agent. Of course, waterconstitutes the remaining essential component of the aqueous blend andis present therein in an amount from about 28% to about 45 by Weight.

The acidulating agent is a phosphorus-containing inorganicacidiccompound having a pH below 7, i.e., inorganic phosphorus acids and theirstrong acid salts, such as orthophosphoric acid (H PO monosodiumdihydrogen orthophosphate (NaH PO pyrophosphoric acid (H P O disodiumdihydrogen pyrophosphate (Na H P otrimetaphosphoric acid (11 F 0tetrametaphosphorie acid (H P O triphosphoric acid (H P O andtetraphosphoric acid (H P O The 3,494,869 Patented Feb. 10, 1970acidulating agent reacts with the coconut oil and tallow soaps to formthe free fatty acids thereof in situ in view of the fact that theacidulating agent has a stronger acidity than the fatty acids in thesoaps. However, very strong acidulating agents, such as mineral acids,for example hydrochloric acid, cannot be used to form the free fattyacid superfatting agent in view of the fact that such acids arecorrosive and incompatible with the other components of the soap bar inthat they impart a deleterious odor and/or color thereto, and their saltby-products frequently have solubilities or other properties, such asefliorescence, which are undesirable. Moreover, the free fatty acidsuperfatting agent must be formed in situ by the interaction of theacidulating agent with the coconut oil and tallow soaps rather than bythe direct blending of free fatty acids into the aqueous blend, becausethe direct blending of free fatty acids, such as stearic acid ormyristic acid, into the aqueous blend is costly and produces superfattedcoconut oil soap bars which suffer from discoloration and poor odor onstorage and inadequate latherability.

After the aqueous blend discussed above has been prepared and thecomponents thereof mixed together, it is then dried to a moisturecontent of from about 5% to about 12% by weight. Thereafter, the driedblend is formed into soap bars by conventional methods.

Turning now to a consideration of .the soap bars of the invention, theyare supenfatted in view of the free fatty acid content therein which isfor-med in situ by the above process. Moreover, the soap bars have thehighly desirable properties of being high lathering, stable againstdiscoloration and odor on storage, non-sandy and nonirritating to theskin. The superfatted soap bars contain from about 40% to about 60%, andpreferably about 48%, by weight of a mixture in the relative proportionsof from about 10% to about 30% by weight of potassium coconut oil soapand from about to about 70% by weight respectively of sodium coconut oilsoap. The preferred mixture consists of from about 5% to about 10% byweight of potassium coconut oil soap and from about 43% to about 38% byweight respectively of sodium coconut oil soap. A minimum of 40% byweight total of coconut oil soap is required in order that the soap barswill be high lathering. However, more than 60% by weight total ofcoconut oil soap is unnecessary and would require impractical highlevels of the in situ formed free fatty acid superfatting agent toprovide acceptable mildness. The above relative amounts of potassiumcoconut oil soap and sodium coconut oil soap are necessary, because iftoo small a proportion of potassium coconut oil soap is used, thefinished bars will be sandy while if too high a proportion of potassiumcoconut oil soap is used, the bars will be too soft and have anexcessive wear rate.

A further essential component of the superfatted soap bars is from about10% to about 35% by weight, and preferably about 16% by weight, ofsodium tallow soap. The amounts thereof are not critical.

A further component of the soap bars of the invention is from about 10%to about 15% by weight, and preferably about 15% by weight, of coconutoil and tallow fatty acids which are formed in situ by interreaction ofthe acidulating agent with the coconut oil and tallow soaps as discussedabove. These fatty acid superfatting agents impart mildness to the soapbars and render them non-irritating to the skin. The level of free fattyacids should be increased as the level of coconut oil soaps isincreased. When the quantity of free fatty acid exceeds 15 by weight,however, the bars tend to be too soft for satisfactory processing andwhen 20% or more free fatty acid is used, the latherability isdecreased.

Another component of the soap bars is from about 3% to about 10% byweight, and preferably about 8% by weight, of a higher sodium contentsalt of the acidulating agent discussed above having a pH above 7 whichis formed as the by-product from the interreaction of the acidulatingagent with the coconut oil and tallow soaps. Such sodium salts include,for example, disodium monohydrogen orthophosphate (Na HPO as theby-product of either or-thophosphoric acid or monosodium dihydrogenorthophosphate and trisodium monohydrogen pyrophosphate (Na HP O as theby-product of either pyrophosphoric acid or disodium dihyd rogenpyrophosphate. Such in situ formed sodium salts help impart firmness aswell as color and odor stability to the soap bars. It will beappreciated that small amounts of the corresponding potassium salts arealso present in the soap bars due to the interreaction of theacidulating agent with the potassium coconut oil soap.

'The remaining essential component of the soap bars is from about 5% toabout 12% by weight, and preferably about by weigh-t, of water whichconstitutes the moisture content of the soap bars after drying theaqueous blend. The amount of moisture present in the soap bars isgoverned by the satisfactory processing properties of the bars, such asextrudability.

T-he superfatted soap bars of the invention and the process for theirpreparation are further illustrated by the following examples.

EXAMPLE 1 The soap boil was prepared containing 3804 pounds of sodiumcoconut oil soap and 1523 pounds of sodium tallow soap. The next soapfrom the boil was then pumped to a crutcher where 835 pounds of coconutoil fatty acid were added followed by neutralization thereof with 225pounds of potassium hydroxide (KOH). At this point small amounts ofpreservatives, namely Versene (the tetrasodium salt of ethylene diaminetetraacetic acid) and butyl hydroxy toluene (BH-T), were added. 665pounds of monosodium dihydrogen orthophosphate was then added. After ashort mixing period, the crutcher slurry was dried in a tubular dryer toabout 10% moisture. The molten soap was then chill rolled and the driedchips fed to a chip mixer where small amounts of perfume and other minoringredients, such as whiteners or colorants etc., were added. The mixedchips were then milled, plodded and stamped into bars by conventionalmeans.

The resultant superfatted soap bar had the following composition:

Components: Percent by weight Sodium coconut oil soap 38.35 Potassiumcoconut oil soap 10.00 Sodium tallow soap 16.12

nut oil fatty acids and 30% tallow fatty Free fatty acids (approximately70% coconut oily fatty acids and 30% tallow fatty The following exampleillustrates a further use of the monosodium dihydrogen orthophosphate ofExample 1 as the acidulating agent.

4 EXAMPLE 2 To a steam jacketed mixer with sigma blade agitator, thefollowing were added, in the order given, with acket steam pressure at10 p.s.i.g.:

Lbs.

Whole coconut oil fatty acids 14.0

BHT, 9.6 gms.

Versene (25% aqueous solution), 38.0 gms.

KOH (45% aqueous solution) 2.6

/20 sodium tallow/coconut oil soap chips at NaH PO 2.3 NaOH (50% aqueoussolution) 3.6

When the last of .the ingredients had been added, the steam pressure wasraised to 40 p.s.i.g. after which heat and agitation were continueduntil the resultant mixture had a water content of about 9%. The mixturewas then chill rolled into chips. The chips were processed into barsafter the addition of small amounts of TiO and perfume in a chip mixerfollowed by milling and plodding by conventional means.

The resultant soap bar had the following composition exclusive of thesmall amounts of titanium dioxide and perfume:

Components: Percent by weight Sodium coconut oil soap 35.0 Potassiumcoconut oil soap 15.0 Sodium tallow soap 19.2 Free fatty acids (fromcoconut oil soap and tallow soap) 15.0 Disodium monohydrogenorthophosphate 7.8 Water 8.0

Total 100.0

The following example illustrates the use of orthophosphoric acid as theacidulating agent.

EXAMPLE 3 The same processing conditions and equipment of Example 2 wereused in this example. The following materials were added to the mixer inthe order given:

Lbs.

Whole coconut oil fatty acids 9.8

BHT, 9.6 gms Versene (25% aqueous solution), 38.0 gms KOH (45.5% aqueoussolution) 2.1

NaOH (50% aqueous solution) 2.4

80/20 sodium tallow/coconut oil soap chips at 14% H O 22.3 H PO (80%aqueous solution) 1.19

The resultant soap bar had the following composition exclusive of thesmall amounts of titanium dioxide and perfume:

Ponents: Percent by weight Sodium coconut oil soap 28,0 Potassiumcoconut oil soap 12.0 Sodinmtallow soap 33.1 Free fatty acids (fromcoconut oil soap and tallow soap) 15.0 Disodium monohydrogenorthophosphate 3.9 Water 8.0

Total 100.0

The following example illustrates the use of disodium dihydrogenpyrophosphate as the acidulating agent.

EXAMPLE 4 The same processing conditions and equipment of Example 2 wereemployed in this example. The following materials were added to themixer in the order given:

The resultant soap bar had the following composition exclusive of thesmall amounts of titanium dioxide and perfume:

Components: Percent by weight Sodium coconut oil soap 33.0 Potassiumcoconut oil soap 7.0 Sodium tallow soap 30.6 Free fatty acids (fromcoconut oil soap and tallow soap) 10.0 N33HP207 Water 10.0

Total 100.0

All of the above bars produced a high lather and were firm and stable onstorage against discoloration and odor. The bars were also non-sandy andnon-irritating to the skin. Comparable results were obtained using otherphosphorus-containing inorganic acidic compounds having a pH below 7 asthe acidulating agent.

It will be appreciated that various compatible adjuvants may be presentin the superfatted soap bars of the invention. Typical examples thereofinclude perfumes, whiteners, fluorescent dyes, preservatives, chelatingagents, etc. Such compatible adjuvants, when employed, are present insmall amounts of under a total of about 5% by weight of the bar.

Since various modifications of the product and process of the invention,in addition to those discussed above, would readily occur to thoseskilled in the soap art without departing from the spirit of theinvention, the invention is to be limited only within the scope of theappended claims.

What is claimed is:

1. A process for the preparation of high lathering, firm, stable,non-sandy, non-irritating superfatted soap bars which comprisespreparing and mixing an aqueous blend consisting essentially of fromabout 25% to about 55% by weight of a mixture in the relative amounts offrom about to about 30% by weight of potassium coconut oil soap and fromabout 90% to about 70% by weight respectively of sodium coconut oilsoap, from about 5% to about 30% by weight of sodium tallow soap, fromabout 2% to about 8% by weight of a phosphorus-containing inorganicacidic compound having a pH below 7 selected from the group consistingof orthophosphoric acid, pyrophosphoric acid, trimetaphosphoric acid,tetrametaphosphoric acid, triphosphoric acid, tetraphosphoric acid andstrong acid salts thereof as an acidulating agent and from about 28% toabout 45% by weight of water; drying the aqueous blend to a moisturecontent of from about 5% to about 12% by weight; and forming the driedblend into soap bars; whereby a portion of the coconut oil and tallowsoaps are acidulated to liberate in situ the free fatty acids thereofand the acidulating agent is converted in part into a higher sodiumcontent salt thereof having a pH above 7.

2. The process as defined by claim 1 wherein the acidulating agent isorthophosphoric acid.

3. The process as defined by claim 1 wherein the acidulating agent ismonosodium dihydrogen orthophosphate.

4. The process as defined by claim 1 wherein the acidulating agent isdisodium dihydrogen pyrophosphate.

5. A high lathering, firm, stable, non-sandy, non-irritating,superfatted soap bar for-med by the process of claim 3 consistingessentially of (a) from about 40% to about 60% by weight of a mixture inthe relative amounts of from about 10% to about 30% by weight ofpotassium coconut oil soap and from about 90% to about by weightrespectively of sodium coconut oil soap; (b) from about 10% to about 35%by weight of sodium tallow soap; (0) from about 10% to about 15% byweight of in situ formed coconut oil and tallow fatty acids; ((1) fromabout 3% to about 10% by weight of a higher sodium content salt having apH above 7 of a phosphorous-containing inorganic acid compound having apH below 7; selected from the group consisting of orthophosphoric acid,pyrophosphoric acid, trimetaphosphoric acid, tetrametaphosphoric acid,tn'phosphoric acid, tetraphosphoric acid and strong acid salts thereofand (e) from about 5% to about 12% by weight of water.

6. A high lathering, firm, stable, non-sandy, non-irritating,superfatted soap bar formed by the process of claim 3 consistingessentially of (a) about 48% by weight of a mixture consisting of fromabout 5% to about 10% by weight of potassium coconut oil soap and fromabout 43% to about 38% by weight respectively of sodium coconut oilsoap; (b) about 16% by weight of sodium tallow soap; (c) about 15% byweight of in situ formed coconut oil and tallow fatty acids; (d) about8% by weight of disodium monohydrogen orthophosphate; and

(e) about 10% by weight of water.

References Cited UNITED STATES PATENTS 2,093,927 9/ 1937 Preston 2521092,310,475 2/ 1943 Thomas 252109 3,047,509 7/ 1962 Alsbury et al. 252-1173,224,976 12/ 1965 Farrar 252119 3,383,320 5/1968 Bell 252132 3,247,1214/ 1966 Hendricks 2521 17 FOREIGN PATENTS 521,566 5/ 1940 Great Britain.

LEON D. ROSDOL, Primary Examiner D. L. ALBRECHT, Assistant Examiner US.Cl. X.R. 252132 "H050 UNITED STATES PATENT OFFICE CERTIFICATE OFCORRECTION Patent No. 3, #94,869 Dated February 10, 1970 Inv n fl.TnsPph Armstrong It is certified that error appears in theabove-identified patent and that said Letters Patent are herebycorrected as shown below:

Column 3, line 55, "nut oil fatty acids and 30% tallow fatty" should bedeleted; line 57', oily should be oil line 59, "monohydrates should bemonohydrogen Column 4, line 9, "45%" should be 45.5%

SIGNED AN'D SEALED Juu41970 Attest:

Edward M. Fletcher, Ir WILLIAM E. 30mm, JR.

Golrmissioner of Patents Attesting Officer

